Ischemic heart disease is still one of the leading causes of death and disability for both men and women globally today.[1 ]The development of a plaque in the epicardial coronary arteries is the hallmark of coronary artery disease. The atherosclerotic plaque often narrows coronary arteries, reducing blood flow in arteries that are big to medium in size.[2 ] Coronary artery disease (CAD) is a tangled condition characterized by the narrowing of the internal width of coronary arteries, leading to myocardial ischemia and infarction. The transluminal diameter of coronary arteries plays a foremost role in CAD pathophysiology, as it affects blood flow and shear stress. This study investigates the effect of the trans-luminal diameter of coronary arteries on the growing and progression of coronary artery disease. Coronary heart disease (CAD) is the leading cause of death worldwide. Despite being manageable, the mortality rate is increasing in developing countries and the disease burden is likely to be doubled by 2020 in these countries. Asian population is more susceptible to heart diseases and a 50 % higher prevalence of cardiovascular diseases has been reported in South Asians.[3]

Between myocardial infarction and sudden cardiac death, chronic stable angina represents one end of the clinical and pathological range of coronary artery disease (CAD). Advances in epidemiological research have demonstrated that factors associated with lifestyle and environment can raise the risk of coronary artery disease (CAD) in addition to the conventional risk factors, which include age, male sex, hypertension, diabetes mellitus, obesity, hypercholesterolemia, smoking, and family history.[4]  A genetic predisposition is also considered to play an essential role in the etiology of coronary artery disease (CAD), as indicated by twin and family studies. This is in addition to the causes listed above.[5]

The diameter of the coronary artery were measured in 140 patients including both genders on CT angiogram. The diameter of proximal left main (LM), the left anterior descending (LAD), left circumflex (LCx), and the right coronary artery (RCA) were measured.

CRITERIA

INCLUSION CRITERIA

1. Subjects between 30 -60 years
2. Subjects of either sex having coronary artery diseases.
3. Subjects having signs and symptoms of CVD.
4. Subjects having primary obesity.

EXCLUSION CRITERIA

1. Subjects below 30 years and more than 60 years.
2. Subjects having severe congenital cardiac anomalies.
3. Subjects who undergone bypass surgery.
4. Obesity produced due to certain secondary cause.
5. Subjects suffering from any grave disease and hospitalization in last 3 months.
6. Endocrinal origin obesity.
7. Subjects who are not willingly to participate in the study.

The diameter of four cardiac arteries (LM, LAD, LCX, and RCA) was assessed in a study at three distinct locations (proximal, mid, and distal).The comparison of mean diameter (in mm) of LM, LAD, LCX and RCA between one-way ANOVA test with inter-group comparison using the post-hoc bonferroni test in which to identify specific differences between segments, Tukey's HSD Test was applied (Table 1.) The results are as follows:

• LM Artery: Proximal vs. Mid: Not significant (mean difference = -0.18, p-value > 0.05), Proximal vs. Distal: Significant (mean difference = -0.33, p-value < 0.05), Mid vs. Distal: Not significant (mean difference = -0.15, p-value > 0.05)
• LAD Artery: Proximal vs. Mid: Not significant (mean difference = -0.21, p-value > 0.05), Proximal vs. Distal: Significant (mean difference = -0.42, p-value < 0.05), Mid vs. Distal: Not significant (mean difference = -0.21, p-value > 0.05)
• LCX Artery: Proximal vs. Mid: Not significant (mean difference = -0.19, p-value > 0.05), Proximal vs. Distal: Significant (mean difference = -0.41, p-value < 0.05), Mid vs. Distal: Not significant (mean difference = -0.22, p-value > 0.05)
• Right coronary Artery: Proximal vs. Mid: Not significant (mean difference = -0.24, p-value > 0.05), Proximal vs. Distal: Significant (mean difference = -0.75, p-value < 0.05), Mid vs. Distal: Significant (mean difference = -0.51, p-value < 0.05)

The analysis reveals significant differences in diameters across segments for all four coronary arteries. Specifically, the diameters tend to increase from the Proximal to the Distal segment. The post-hoc comparison results indicate that the significant differences primarily lie between the Proximal and Distal segments for LM, LAD, and LCX arteries. For the RCA artery, significant differences are found between both Proximal vs. Distal and Mid vs. Distal segments.

The comparison of mean Diameter of Right and Left coronary artery in mm between one-way ANOVA test with inter-group comparison using the post-hoc bonferroni test showed that mean Diameter of Right and Left coronary artery in mm was significantly more among Distal compared to Middle which was significantly more among Proximal.(Table.2)

The left coronary artery has larger diameters 4.25-4.47 mm than the right coronary artery  2.99-3.32 mm at all segments. The left coronary artery has larger diameters than the right, which may be related to differences in blood flow demands. The left coronary artery's larger standard deviations in mid and distal segments may indicate greater variability.

STATISTICAL ANALYSIS -The comparison of mean diameter (in mm) of LM, LAD, LCX and RCA between one-way ANOVA test with inter-group comparison using the post-hoc bonferroni test.

Table 1: Describing the study groups as per the comparison of mean diameter (in mm) of LM, LAD, LCX and RCA. The results indicate significant differences in diameters across segments for all four coronary arteries (p < 0.05).

Table 2: Describing the study groups as per the comparison of mean Diameter of Right and Left coronary artery in mm. The results indicate significant differences in diameters across segments for both the right (p = 0.014) and left (p = 0.037) coronary arteries.

This study aimed to evaluate the diameters of the right coronary artery (RCA) and the sub-branches of the left coronary artery (LCA) — namely, the left main (LM), left anterior descending (LAD), and left circumflex (LCX) arteries — in 140 patients. Using coronary angiography, we measured the arterial diameters at three anatomical segments: proximal, mid, and distal. Clinical patient data supported the analysis to better understand potential correlations with coronary artery disease (CAD).

Our results demonstrated a clear pattern in arterial diameter variation across the three segments. Notably, the distal segments of all examined arteries exhibited the largest diameters, followed by the mid segments, while the proximal segments had the smallest diameters. This indicates an increasing trend in diameter from the proximal to distal end of the coronary arteries — a finding contrary to conventional anatomical expectations, where proximal segments are generally assumed to be larger.

These findings suggest that coronary artery diameter measurements, especially in specific arterial segments, may serve as a valuable predictor of CAD risk. While prior studies have primarily focused on arterial diameters to aid treatment strategies for CAD, few have systematically examined coronary diameter as a predictive or diagnostic parameter throughout the disease course.

CAD remains a major health burden, accounting for approximately 610,000 deaths annually in the United States (about 1 in 4 deaths) and ranking as the third leading cause of mortality globally, with an estimated 17.8 million deaths each year. Previous literature highlights wide variation in coronary artery diameters, influenced by genetic, environmental, and demographic factors such as age, sex, race, and ethnicity [11–14]. Although a definitive consensus on sex-based differences in artery size remains elusive, several studies have proposed the existence of gender-related variation [15].

In our study, we observed a significantly smaller coronary artery diameter in patients with CAD. Furthermore, there was an inverse relationship between artery size and the severity of coronary lesions. These findings align with the hypothesis that smaller arterial diameters are independently associated with a higher prevalence and severity of CAD. The underlying mechanisms driving the association between smaller artery diameter and more severe coronary lesions are not yet fully understood. However, recent evidence suggests that coronary artery diameters may correlate with the extent of coronary artery calcification, offering a possible pathophysiological explanation [16]. Interestingly, our study also found that Asian-Indian patients had significantly smaller coronary artery diameters compared to white individuals, even when body surface area (BSA) was similar between groups. This contrasts with previous research by Lip et al. and Dhawan & Bray [7,8], who attributed smaller coronary sizes in Asian-Indians primarily to smaller BSA. Our findings suggest that factors beyond BSA may be contributing to these ethnic differences [17,18]. Supporting this, Kim et al. [19] demonstrated through intravascular ultrasound that both gender and BSA are independent predictors of coronary artery size, although BSA had a more pronounced impact. These variations underscore the need to consider demographic and anthropometric diversity when interpreting coronary angiographic data and developing risk stratification tools.

In conclusion, our findings expand the current understanding of coronary artery morphology and highlight the potential of using coronary artery diameter as a non-invasive marker in CAD assessment. Further large-scale, multiethnic studies are warranted to validate these results and explore the biological mechanisms underpinning these associations.

Trans-luminal diameter has an important impact on the development of CAD, as this study shows. Reducing trans-luminal diameter is associated to a higher incidence of CAD, highlighting its significance in the recognition and management of CAD. These findings have consequences for creating individualized treatment plans and enhancing patient outcomes. The underlying mechanisms and possible treatment targets associated with transluminal diameter in CAD require further investigation.

This discovery holds significant therapeutic ramifications, as narrower coronary arteries can result in technical challenges during intervention operations including atherectomy, stent implantation, and percutaneous trans-luminal coronary angioplasty.

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